Superb! Rated 5 out of 5 stars

Some suggestions:
1. Make active tab more noticeable - may be bigger itself or bigger text
2. If the text color and background color is similar, automatically generate text color by inverting background color
3. May be if no background image is available extension may use predominant color of page?

I'll follow for updates for this unic extension

This review is for a previous version of the add-on (0.7.3).